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Biomedical subjects

L Baldassarre

Publications and source records attributed to L Baldassarre.

14 recordsLinked to original sources
PubMed2006

Low-energy electrodynamics of superconducting diamond.

Heavily boron-doped, diamond films can become superconducting with critical temperatures Tc well above 4 K. Here we first measure the reflectivity of such a film down to 5 cm(-1), by also using coherent synchrotron radiation. We thus determine the optical gap 2Delta, the field penetration depth lambda, the range of action of the Ferrell-Glover-Tinkham sum rule, and the electron-phonon spectral function alpha2F(omega). We conclude that diamond behaves as a dirty BCS superconductor.

Journal Article↗
PubMed2003

Seventeen novel HLA-A alleles.

This paper describes 17 novel HLA-A alleles: A*0244, A*0251, A*0254, A*0309, A*1111, A*2432, A*2434, A*2504, A*2618, A*2905, A*2906, A*3106, A*3107, A*3207, A*6820, A*7407, and A*7408. Most substitutions are found in other alleles.

Alleles↗
PubMed2003

Twenty-five novel HLA-B alleles.

Twenty-five novel HLA-B alleles are described in this paper: B*0729, B*1309, B*1814, B*1815, B*2724, B*2725, B*3539, B*3926, B*4037, B*4040, B*4042, B*4043, B*4044, B*4204, B*440203, B*4428, B*4429, B*4430, B*4505, B*5308, B*5309, B*5510, B*5511, B*570102, and B*5709. Most of the variants are single nucleotide substitutions. Two involve variants at the Bw4/Bw6 epitope. Two alleles carry substitutions of conserved amino acids.

Alleles↗
PubMed2002

Novel HLA-B alleles formed by an inter-locus recombination with HLA-C, HLA-B*0713 and B*6702.

This paper describes two novel HLA-B locus alleles. B*0713 appears to have resulted from an interlocus recombinational event which inserted a sequence from an HLA-C allele into B*0702. This event altered a significant portion of the alpha-1 domain alpha helix. B*6702 shares much of its exon 2 sequence with B*0713 but is identical in exon 3 to several HLA-B locus alleles including B*67012.

Alleles↗
PubMed2002

A comparison among different methods for evaluating the biomass activity in activated sludge systems: preliminary results.

In order to improve activated sludge plant operation (achieving higher efficiency and cost savings) beside influent and effluent characteristics and working parameters (e.g. dissolved oxygen, total and volatile suspended solids, pH, recirculation flow rate, etc.), the biomass activity should be monitored, the bacteria being responsible for the pollutant degradation. Since conventional cultivation based methods are inadequate to quantify environmental microorganisms (due to scarce number of cultivable microorganisms and time-consuming procedures) several "non-conventional" techniques were applied in this study, in order to compare the obtainable information and their routine feasibility. Different measurements (VSS concentration, Oxygen Uptake Rate, microbial counts by cultural and biomolecular methods--MPN-PCR, ATP content, dehydrogenase activity, microbial cell viability and enzymatic activity) were carried out on mixed liquor samples, taken from a municipal activated sludge plant (440,000 p. e.). The preliminary results of the research are presented in this paper.

Adenosine Triphosphate↗
PubMed1990

Prediction of the interaction effects Ar+ laser-brain tumours by study of the photoacoustic spectroscopy of cerebral oncotypes.

A preliminary definition of light absorption spectra of brain neoplasm represents a correct approach to the laser therapy of cerebral tumours. The goal should be the identification of those oncotypes more sensive to the laser energy, allowing consequently a dosage of the energy proportional to the light absorption coefficient, reducing any side effects. With this purpose the coefficients of light-absorption of 63 different brain tumours have been analyzed and defined by means of photocoustic spectrometry. The study has been focused at wavelength of the Ar+ laser (4,600-6,000 A). The results show a close relationship between histology, degree of vascularization and/or pigmentation and light absorption: the more immature and/or pigmented oncotypes show the highest coefficients of optical absorption. In the laser therapy of these neoplasms it will be sufficient to use low powers and short exposure time.

Animals↗
PubMed1986

Evaluation of the Ar+ laser thermal effect in rabbit brain tissue by means of optical absorption coefficients. Photoacoustic measurements.

In predicting Ar+ laser-neural tissue interaction a determination of the optical absorption properties of brain parenchyma appears indispensable. In this study a determination of absorption spectra of different areas of rabbit brain at the wavelength of an Ar+ laser beam is made. The areas considered in the study are frontal and occipital gray and white substance, thalamus, basal ganglia, cerebellar cortex and choroid plexus. Specimens of these areas measuring 2 X 3 X 3 mm were obtained from coronal sections 1 cm thick of 20 rabbit brains. The analysis of optical properties was made by means of a photoacoustic spectrometer which appears the only suitable technique for testing the optical absorption properties of biological materials. The absorption coefficient results were similar in magnitude and constant in all the areas examined, measuring approximately 50 cm-1. The prediction of lack of any selective effect for the different areas is confirmed by the sizes of lesions made in cerebral specimens of the same areas of the contralateral hemisphere by means of Ar+ laser: the lesions increase in size in proportion to the increase in output power and exposure time, independently of the areas considered. Also the histological examination of the areas shows the same morphology to be independent of the variations of both output power and exposure time. The only differences were the presence for short exposure time and low output power of a carbonized layer inner to the layer of coagulative necrosis.

Absorption↗
PubMed1982

[Thermal effects of Nd:YAG and Co2 lasers on biological tissues].

The surgical use of CO2 c.w. laser as a knife and of Nd:YAG laser as photocoagulator is generally explained in terms of the different absorption coefficients of the water contained in high amount in the living tissues at the operating wavelengths of the two sources (alphaCO2 congruent to 10(2) cm(-1), alpha Nd congruent to 1cm(-1)). This approach can be shown to be incorrect once spectrophotometric measurements carried out on a mucous membrane and blood give the values gammaCO2 = 200 cm(-1) and gamma Nd = 10 cm(-1) for the effective absorption coefficient (the effective coefficient is gamma = alpha + beta where beta is the internal light scattering coefficient). It is worth noting that gammaCO2 congruent to alpha CO2 but gammaNd congruent to 10alphaNd. Then we have calculated the temperature distribution on tissues irradiated either by Co2 or by Nd laser. In the Co2 irradiation two energy transfer mechanisms are present: the surface optical absorption and the thermal diffusion in the bulk of the tissue. Under Nd irradiation the optical absorption of internally scattered radiation must also be taken into account. The calculation model is based on the classical heat equation, but assuming a "source" given by the expression S (r,z; t) = alpha [IB (r,z; t)+IS (r,z;t)], where IB and IS are respectively the direct and scattered components of a beam propagating along a z direction perpendicular to the tissue surface. The general expression of the temperature increases deltaT (r,z;t) have been obtained for both laser sources. The calculation show that even a few watts CO2 laser can induce a surface temperature rise of about 60 degrees C with negligible bulk effects, depending only on the thermal conductivity and on the irradiation time (knife effect). On the contrary a 40 w Nd:YAG laser induces a 50 degrees C temperature rise in the whole thickness of the tissue becoming in this way unable to "cut" even though it coagulates a region much larger than the beam dimensions.

Carbon Dioxide↗
PubMedDate not supplied

Bilateral cervical posterior rhizotomy: effects on dystonia and athetosis, on respiration and other autonomic functions.

Bilateral cervical posterior rhizotomy of C1 through C4, C5 or C6 was performed in 16 patients affected by dystonia and athetosis resulting from infantile cerebral palsy. The majority showed decreased muscle spasms and athetoid movements, with some improvements in their posture and voluntary mobility. 5 patients suffered from uneven and irregular breathing associated with lethargy immediately postoperatively, and 4 also showed reduced diaphragmatic activity; all 4 of these patients developed pneumonia, transitory in 3, but fatal to the other. Urinary retention lasting for a maximum of 3 months occurred in 4 of the 5 patients. The authors suggest that the lesion of ascending reticular fibers in the cervical posterior roots could have been responsible for the observations.

Adolescent↗
PubMedDate not supplied

[Clinical study of dantrolene sodium in the treatment of spastic and dystonic syndromes].

Dantrolene sodium has been given to 45 patients suffering from dyskinetic syndromes: 33 were suffering from spastic syndromes, either secondary to cerebral lesions at birth, or to other cerebral lesions, or to cord lesions; 9 were affected by infantile dystonic syndromes; 1 by dystonia muscolorum deformans and the last 2 patients were suffering from parkinsonism. The best dosage schedule was individual and ranged from 50 mg to 300 mg a day. In this range, the majority of the spastic patients showed reduction of spasticity, unrelated with the site of pathology: a slight one in 12 patients, a moderate one in 9 and a marked one in 2. On the contrary, slight improvement has been noticed in only two of the patients suffering from dystonic syndromes. In no case side effects has been noticed. In all patients who underwent slight or moderate improvement only, we tried to obtain better results on spasticity by growing the dosage schedules; but we have always noticed side effects, that is weakness or drowsiness and, sometimes, urinary uncontinence. Moreover 2 patients showed evidence of transitory metabolic side effects. Therefore our experience shows that dantrolene sodium is an useful drug into the therapy of spasticity, even if often a slight of moderate improvement only is achieved. Slow increase in dosage schedule, repeated laboratory controls and alternate periods of treatment and suspended treatment should be observed.

Adolescent↗
PubMedDate not supplied

Chronic paleocerebellar stimulation in dystonia and athetosis. Report of two cases.

Two patients suffering from dystonia and athetosis have been treated by means of chronic electrical stimulation of the paleocerebellum and were followed for over two and a half years. One of the patients showed signs of slight improvement, while no improvement at all was observed in the other patient. Some observations and problems are discussed.

Adult↗
PubMedDate not supplied

[Selective posterior radiculotomy in the treatment of spasticity: immediate and long-term results].

Immediate and late results of a series of 44 patients suffering from spastic syndromes, operated on from January 1973 to December 1976 by selective posterior rootlet section, have been analyzed and reported. The operation consisted of a selective section of the dorsomedial part of the rootlets constituting each posterior root and was performed usually from L1 to S1 bilaterally. Thirty patients improved markedly after the operation and there were no immediate or late complications. The procedure caused no sensory disorders. The indications and contraindications to the operation are discussed.

Adolescent↗
PubMedDate not supplied

[Diagnostic and therapeutic problems in dystonia musculorum deformans].

Taking as starging point three patients who unsuccessfully underwent both medical treatment and different neurosurgical interventions, the Authors discuss the problem of the dystonia musculorum deformans nosographic arrangement and its present therapeutical possibilities. They believe that the dystonia musculorum deformans must be considered, rather than as a syndrome, as a real disease, to be distinguished in particular from the various infantile dystonic syndromes and from spasmodic torticollis. In fact in these last morbid forms, at least from a neurosurgical standpoint, the therapeutical possiblities are not so uncertain as those of the dystonia musculorum deformans.

Adolescent↗